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Find inverse of the following matrices (if they exist) by elementary transformations : [1-123] - Mathematics and Statistics

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प्रश्न

Find inverse of the following matrices (if they exist) by elementary transformations :

`[(1, -1),(2, 3)]`

बेरीज

उत्तर

Let A = `[(1, -1),(2, 3)]`

∴ |A| = `|(1, -1),(2, 3)|`

= 3 + 2
= 5 ≠ 0
∴ A–1 exists.
Consider AA–1  = I

∴ `[(1, -1),(2, 3)] "A"^-1 = [(1, 0),(0, 1)]`

Applying R2 → R2 – 2R1, we get

`[(1, -1),(0, 5)] "A"^-1 = [(1, 0),(-2, 1)]`

Applying R2 → `(1/5)` R2, we get

`[(1, -1),(0, 1)] "A"^-1 = [(1, 0),(-2/5, 1/5)]`

Applying R1 → R1 – R2, we get

`[(1, 0),(0, 1)] "A"^-1 = [(3/5, 1/5),(-2/5, 1/5)]`

∴ A–1 = `[(3/5, 1/5),(-2/5, 1/5)]`.

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पाठ 2: Matrices - Miscellaneous Exercise 2 [पृष्ठ ८५]

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बालभारती Mathematics and Statistics 1 (Commerce) [English] 12 Standard HSC Maharashtra State Board
पाठ 2 Matrices
Miscellaneous Exercise 2 | Q 4.16 | पृष्ठ ८५

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